1. Field of the Invention
The present invention relates to data storage media for storing digital data, and particularly, to data storage media having certification data.
2. Description of the Related Art
Various types of information in characters, images, video, and audio are presently handled as digital data. To record digital data and programs, a variety of storage media such as tapes, floppy disks, hard disks, and magneto-optical disks are used.
The floppy disks are one of popular media. When data are written or read, the floppy disks need to be rotated. Therefore, the disk-drives must have a motor and a rotating mechanism. Due to this, the floppy disks are improper for electronic devices that must be small and light.
Portable electronic devices need external data storage media that are small and light and ensure compatibility among various types of electronic devices.
Data storage media that meet these requirements are those having nonvolatile semiconductor memories which are electrically rewritable. For example, card-type data storage media incorporating nonvolatile semiconductor memories are suitable for the portable electronic devices. Many techniques have been developed to record contents such as still images, voice, and music in the card-type data storage media.
Unlike analog data, digital data never deteriorates even if it is repeatedly copied among data storage media. It is required, therefore, to provide a technique of preventing the illegal copying of digital contents.
In particular, electronic commerce and electronic banking must prevent the illegal alteration and copying of data, in particular, personal identification data stored in data storage media.
A first object of the present invention is to provide data storage media, data recorders, and data readers capable of preventing the illegal copying of digital data.
A second object of the present invention is to provide data storage media that secure the safety of certification data stored therein from alteration.
In order to accomplish the objects, an aspect of the present invention provides a data storage medium having a first semiconductor memory area that is read-only and stores first certification data that is unique to the data storage medium, a second semiconductor memory area that stores data and second certification data supplied from the outside, an identity circuit for determining whether or not the first and second certification data are identical with each other, and a switch circuit for providing the data stored in the second semiconductor memory area to the outside only when the identity circuit determines that the first and second certification data are identical with each other.
When an external device records data in the data storage medium of this aspect, the data storage medium passes the first certification data to the external device. Then, the external device records data and the first certification data in the data storage medium. The first certification data recorded at this time is used as second certification data. By testing to see if the first and second certification data are identical with each other, an illegal alteration of certification data can be checked. If an illegal alteration of certification data is detected, no data is provided from the data storage medium to the outside, thereby preventing illegal data copying.
The identity circuit may be configured to determine whether or not the second certification data is identical with third certification data, which is generated from the first certification data.
Another aspect of the present invention provides a data storage medium having a semiconductor element. The semiconductor element has a first memory area, a second memory area, first wiring for controlling data write and erase operations of the first memory area, a first terminal for controlling the first wiring, second wiring for controlling a data write operation of the second memory area, and a second terminal for controlling the second wiring. The data storage medium further has an external terminal connected to the second terminal and electrically separated from the first terminal, and a support material for supporting the semiconductor element and external terminal so that the semiconductor element is covered with the support material and the external terminal is exposed from the support material. The first memory area stores certification data that identifies the semiconductor element.
According to this aspect, the first wiring for controlling the write and erase operations of the first memory area is controlled through the first terminal, which is electrically separated from the external terminal, so that the certification data stored in the first memory area will never be altered through the external terminal. This arrangement is simple to protect the certification data stored in the first memory area from an illegal alteration.
Still another aspect of the present invention provides a method of manufacturing a data storage medium. The method includes the step of forming semiconductor elements on a semiconductor substrate. Each of the semiconductor elements has a first memory area, a second memory area, first wiring for controlling data write and erase operations of the first memory area, second wiring for controlling a data write operation of the second memory area, a first terminal for controlling the first wiring, and a second terminal for controlling the second wiring. The method further includes the steps of writing unique certification data in the first memory area of each of the semiconductor elements, cutting the semiconductor substrate to separate the semiconductor elements from one another into semiconductor chips, arranging each of the semiconductor chips on a wiring board having an external terminal, and connecting, for each of the semiconductor chips, the second terminal to the external terminal and sealing each of the semiconductor chips so that the first terminal is electrically isolated.
This method writes unique certification data into the first memory area of each semiconductor element during manufacturing. Thereafter, the method seals the first terminal for controlling the first wiring that controls the write and erase operations of the first memory area, so that the first terminal is isolated from the external terminal. This method is simple to make the first memory area unalterable, thereby protecting the certification data stored in the first memory area from illegal manipulation.
Still another aspect of the present invention provides a data recorder for recording data in a data storage medium having a semiconductor memory that stores certification data unique to the data storage medium. The data recorder has a data processing unit. The data processing unit has a memory for storing a first code that is unique to the data processing unit, a unit for acquiring the certification data from the data storage medium, a unit for generating a second code based on the first code and the certification data, a unit for encoding the data based on the second code, and a unit for writing the encoded data into the data storage medium.
According to this aspect, each data storage medium is provided with unique certification data, and the data processing unit of the data recorder has a unique first code. The certification data and first code are used to generate a second code. The second code is used to encode data, and the encoded data is recorded in the data storage medium. To decode and reproduce the data recorded by the data recorder, the second code must be used. Namely, the certification data of the data storage medium and the first code unique to the data processing unit of the data recorder are imperative to recover meaningful data from the data storage medium. In other words, the meaningful data will never be collected from any data storage medium that does not have the certification data, or with any data reader that does not have the first code. This prevents illegal data copying.
The memory or data processing unit for storing the first code may be a second data storage medium attached to the data recorder.
Still another aspect of the present invention provides a data reader for reading data from a data storage medium having a semiconductor memory that stores certification data unique to the data storage medium. The data reader has a data processing unit. The data processing unit has a memory for storing a first code unique to the data processing unit, a unit for acquiring the certification data from the data storage medium, a unit for generating a second code based on the first code and certification data, a unit for reading the data from the data storage media, and a unit for decoding the read data based on the second code.
This data reader is capable of reading data that has been recorded in a data storage medium by the recorder mentioned above. The data reader acquires unique certification data from the data storage medium, generates a second code based on the certification data and first code, and uses the second code to read data as meaningful informations from the data storage medium.
The memory or data processing unit for storing the first code may be a second data storage medium attached to the data reader.
Still another aspect of the present invention provides a data storage medium removably attached to a data recorder that records data in a second data storage medium having a semiconductor memory that stores certification data unique to the second data storage medium. The data storage medium has a memory for storing a first code that is unique to the data storage medium, a unit for acquiring the certification data from the second data storage medium, a unit for generating a second code based on the first code and acquired certification data, a unit for receiving data from the data recorder, a unit for encoding the received data based on the second code, and a unit for writing the encoded data into the second data storage medium. The data storage medium may have CPU.
Still another aspect of the present invention provides a data storage medium removably attached to a data reader that reads data from a second data storage medium having a semiconductor memory that stores certification data unique to the second data storage medium. The data storage medium has a memory for storing a first code that is unique to the data storage medium, a unit for acquiring the certification data from the second data storage medium, a unit for generating a second code based on the first code and acquired certification data, a unit for reading the data from the second data storage medium, and a unit for decoding the read data based on the second code.
The data storage medium mentioned above is attached to a data recorder or a data reader, to serve as a data processing unit of the data recorder or reader. Since the data storage medium is removable from the data recorder or reader, the data recorder or reader may commonly be used for many data storage media. The first code stored in the data storage medium may be data related to a specific person, and this person may keep the data storage medium to secure the safety of the data.